Ball cam centering mechanism

ABSTRACT

A universal joint ( 300 ) includes a centering device ( 110 ) for supporting the universal joint and forcing the two joint halves to operate at the same angle thereby causing the joint to operate at constant velocity at all angles. Each shaft ( 115, 116 ) of the joint ( 300 ) is connected to the centering device ( 110 ). Movement of one of the shafts ( 115, 116 ) at an angle relative to the longitudinal axis of the coupling device ( 317 ) is transmitted to the other shaft ( 116, 115 ) by the centering device ( 110 ) and the centering device ( 110 ) causes the other shaft ( 116, 115 ) to likewise move at the same angle relative to the longitudinal axis of the coupling device ( 317 ). The centering device ( 110 ) includes a cam bearing (cam  101 ) longitudinally aligned with a cam bearing (cam  102 ), which arrangement of cam bearings allows a full range of movement of the shafts ( 115, 116 ).

CROSS-REFERENCE TO RELATED APPLICATIONS

Hereby incorporated by reference are all of my prior patents, includingU.S. Pat. No. 5,823,881 and all references cited therein.

U.S. Pat. application Ser. No.09/173,614, filed Oct. 16, 1998, is alsoincorporated herein by reference.

Priority of my U.S. Provisional Patent Application Serial No.60/112,220, filed Dec. 14, 1998, incorporated herein by reference, ishereby claimed.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable

REFERENCE TO A “MICROFICHE APPENDIX”

Not applicable

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to centering devices. More particularly,the present invention relates to centering devices for universal joints

2. General Background of the Invention

Universal joint designers have found it difficult to design constantvelocity universal joints capable of operating at high angles, highspeeds and high loads simultaneously, due to the limitations of existingconstant velocity universal joint centering and supporting devices. Thisis due to the difficulty in packaging robust internal supporting devicesthat utilize rolling elements that are capable of operating at typicaldriveline speeds. Self supported universal joints capable of operatingat constant velocity at high angles, high speeds and high torque loadsprovide design engineers with the following options: higher powertransfer capability to driven members (ex. wheels, power takeoffs); moreoptions in drive-line placement; engines can be run at higher r.p.m.resulting in greater fuel economy; and tighter turning radiuses forvehicles.

See U.S. Pat. No. 5,823,881 and all references cited therein for morebackground of the invention.

BRIEF SUMMARY OF THE INVENTION

The apparatus of the present invention solves the problems confronted inthe art in a simple and straightforward manner. What is provided is aball cam centering mechanism. In a preferred embodiment of the presentinvention, the ball cam centering mechanism comprises a dual in-line camcentering device for universal joints. The invention is advantageousbecause it supports the universal joint with robust components in arelatively small package while allowing the universal joint to operateat high angles of misalignment.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

For a further understanding of the nature, objects, and advantages ofthe present invention, reference should be had to the following detaileddescription, read in conjunction with the following drawings, whereinlike reference numerals denote like elements and wherein:

FIG. 1 is a perspective, partially sectional view of a first embodimentof the universal joint apparatus of the present invention with noangular joint displacement;

FIG. 2 is a perspective, partially sectional view of the firstembodiment of the universal joint apparatus of the present inventionwith angular joint displacement;

FIG. 3 is a perspective view of a cage for roller bearings;

FIG. 4 is a perspective, partially sectional view of a second embodimentof the universal joint apparatus of the present invention with noangular joint displacement;

FIG. 5 is a perspective, partially sectional view of the secondembodiment of the universal joint apparatus of the present inventionwith angular joint displacement;

FIG. 6 is a perspective, partially exploded view of the secondembodiment of the universal joint apparatus of the present inventionwith no angular joint displacement;

FIG. 7 is a perspective, partially sectional view of the preferredembodiment of the universal joint apparatus of the present inventionwith angular joint displacement;

FIG. 8 is a perspective, partially sectional view of the preferredembodiment of the universal joint apparatus of the present inventionwith no angular joint displacement; and

FIG. 9 is a perspective, partially exploded view of the preferredembodiment of the universal joint apparatus of the present inventionwith no angular joint displacement.

DETAILED DESCRIPTION OF THE INVENTION

Joint 100 (shown in FIGS. and 2) is a 30 degree joint. Joint 100includes shafts 15 and 16, rings 31 and 32, and an integral couplingmember and dual yokes 117 (which can be the same part as part 117 inU.S. Pat. No. 5,823,881, with similar or same pins interconnecting it tothe rings. The ball cam centering mechanism 10 of the first embodimentof the present invention includes cams 1 and 2. Cam 1 is preferably madeof ball members 11 and 12 fixedly attached to a rod 13. Cam 2 includesball members 21 and 22 fixedly attached to one another with acylindrical member (this cylindrical member and the ball members 21 and22 could be integral). Cam 2 includes a bore 14 for receiving rod 13 ofcam 1.

Dual purpose rollers 17 allow rotational movement of ball members 11,12, 21, and 22 relative to shafts 15 and 16. Rollers 17 are received inbore 18 in shaft 15 and in bore 28 in shaft 16. Cages 19 support rollers17. Seals 20 seal open end of bores 18 and 28 to ball portions 21 and 22of cam 2 to allow lubricating grease to fill bores 18 and 28 and to keepforeign objects out of bores 18 and 28.

Shaft 15 includes a first pin projection 41 and a second pin projection42. Shaft 16 includes a first pin projection 43 and a second pinprojection 44.

First, second, third, and fourth pin members 51, 52, 53, and 54 arereceived in pin projections 41, 42, 43, and 44, respectively. Bearingassemblies 61 and 62 rotatably secure pin members 51 and 52,respectively, in ring 31 and bearing assemblies 63 and 64 rotatablysecure pin members 53 and 54, respectively, in ring 32, to join ring 31to shaft 15 and ring 32 to shaft 16. Similar pin members and bearingassemblies join rings 3l and 32 to integral coupling member and dualyokes 117.

The rolling elements 17 of the present invention allow high speed jointrotation at high joint angles. Dual purpose rollers 17 are in sphericalcontact with the four spherical portions of cams 1 and 2 (ball members11 and 12 and ball portions 21 and 22) and are in cylindrical contactwith bores 18 and 28 of shafts 15 and 16.

Displacement of cam 1 in relation to cam 2 allows misalignment of shaft15 in relation to shaft 16.

The present invention could also be used to join two tubes, even if notpart of a universal joint (such as in robotics applications).

Cam 1 is preferably made of ball members 11 and 12 fixedly attached torod 13.

Ball members 11 and 12 can be integral with rod 13. Assembly of constantvelocity universal joint 200

Universal joint 200 is shown in FIGS. 4-6. Universal joint 200 is aconstant velocity 30 degree joint.

Universal joint 200 can be assembled by the following method: First:Assembly of the centering mechanism 210

Two seals 220 (not shown in FIG. 6) are placed back-to-back over cam202. Ball member 221 is inserted into notch 285 of race 279 and rotatedso that the axis of the hole 223 in ball member 221 is coincident withthe axis of the hole in race 279. This method is repeated with ballmember 212 and race 277. The assembly of ball member 221 into race 279is similar to the slotted entry method of assembling rod end bearings.Ball members 221 and 222 with races 279 and 278, respectively, attachedthereto are attached to each end of cam 202. Ball members 221 and 222can be integral with cam 202 or otherwise fixedly attached to oneanother. Rod 213 is inserted into hole 214 of cam 202. Ball members 211and 212 are assembled into races 280 and 277, respectively, in the samemanner as ball member 221 was assembled into race 279. Ball members 211and 212 with races 280 and 277 attached thereto are attached to the endsof rod 213 forming cam 201. Ball members 211 and 212 can be attached bypressing female spline 291 in ball member 211 onto splines 281 of rod213 and repeating that process with ball member 212 on the other end ofrod 213. Pins 274 and 276 are pressed into the holes 292 at each end ofrod 213. A full complement of needle roller bearings 282 is assembledinto groove 286 of bearing race 279. A full complement of needle rollerbearings 282 is assembled onto races 277, 278 and 280 as bearings 282were assembled into groove 286 of race 279. Bearing cup 283 is insertedover needle roller bearings 282 on races 280 and 279 until the round endof pin 274 contacts the bottom of bearing cup 283. Seal 220 is theninserted in to open end of bearing cup 283. This process is repeatedwith bearing cup 284 inserted over needle bearing rollers 282 on races277 and 278 and seal 220 pressing into the open end of cup 284. Thiscompletes the assembly of the centering mechanism.

The assembly of the remainder of joint 200 is similar to the assembly ofprior art joints.

Ring 231 is placed over shaft 215 such that holes 233 in ring 231 are inalignment with the holes 234 in shaft 215. Trunnion pins 251 and 252 arepressed into the holes 234 in shaft 215 and bearing cups 261 and 262with seals 295 and roller bearings 296 are pressed into holes 233 ofring 231. Connecting yoke 217 is inserted between ring 231 and shaft 215and trunnion pins 255 and 256 are pressed into holes 246 of yoke 217 andbearing cups 265 and 266 are pressed into holes 245 of ring 231. Ring232 is attached to connecting yoke 217 by pressing pins 257 and 258 intoholes 247 of yoke 217 and pressing bearing cups 267 arid 268 into holes245 of ring 232. Centering device assembly 210 is inserted through ring232, connecting yoke 217 and into bore 218 of shaft 215. Shaft 216 isinserted over the other end of centering assembly 210 such that theholes 249 in shaft 216 are aligned with the holes 233 of ring 232.Trunnion pins 253 and 254 and bearing cups 263 and 264 are inserted intoholes 233 of ring 232 and holes 249 of shaft 216 to complete theassembly of joint 200.

Rod 213, with ball members 211 and 212 fixedly attached thereto, makesup cam 201. Rod 213 of cam 201 rotates in hole 214 of cam 202, whichincludes ball members 221 and 222 fixedly attached thereto. Shafts 215and 216 are rotatable with respect to ball members 211, 212, 221, and222.

Cams 201 and 202 cause shafts 215 and 216 to assume the same angle withrespect to the longitudinal axis of coupling yoke member 217.

Universal joint 300, shown in FIGS. 7-9, is a constant velocity 65degree joint.

Assembly of joint 300

Disk springs 170 (such as National Disk Spring Part No. Am188207) areplaced into the bottom of bore 118 in shaft 115 and bore 128 in shaft116. Three piece friction ring 168 is placed in bore 118 of shaft 115and onto disk spring 170. Thrust bearing race 169 is placed withinthree-piece friction ring 168. Ball bearings 171 are placed into groovesof thrust bearing race 169. Cam ball race 167 is inserted into bore 118of shaft 115 and spacer rings 129 and needle bearings 166 are insertedbetween bore 118 and cam ball race 167. Seal 120 is pressed in to openend of shaft 115. This same procedure is repeated with similarcomponents in shaft 116. Rod 113 is inserted into hole 114 of cam 102.Ball members 111 and 112 are pressed onto splines 181 of rod 113.Expansion pins 174 and 176 are pressed into holes 182 of rod 113,expanding holes 182 to secure the ends of rod 113 to ball members 111and 112, completing the assembly of cam 101.

Shaft 116 with disk spring 170, three piece friction ring 168, thrustbearing race 169, ball bearings 171, cam ball race 167, spacer rings129, needle bearings 166, and seal 120 installed therein is assembled onto ring 132 as described for joint 200. Connecting yoke 317 is assembledonto ring 132 as described for below in conjunction with ring 131, withbearing cups 173 pressed into holes 145 in ring 132. Ring 131 isassembled onto connecting yoke 317 as described for joint 200;specifically, holes 145 of ring 131 are aligned with holes 346 of yoke317, and pins 155 and 156 are pressed into holes 346, and bearingassemblies 165 and 172 are pressed into holes 145 of ring 131.

Bearing assemblies 161-165, 172, and 173 can be held in place by anycommonly practiced bearing retention technique used in universal joints;for example, they could be staked into place, could be secured with snaprings, or spherical bands such as band 275 could be used to secure themin place.

Ball cams 101 and 102, now assembled onto one another, are insertedthrough ring 131 and connecting yoke 317 and pressed through seal 120such that ball 122 fits into the tapered opening 180 of cam ball race167. Shaft 115 is inserted into ring 131 and yoke 317 such that ballcams 101 and 102 are pressed through seal 120 and ball member 121 fitsinto the tapered opening 180 of cam ball race 167. Shaft 115 isassembled onto ring 131 as described for joint 200. Specifically, holes134 in shaft 115 are aligned with holes 133 in ring 131, and pins 151and 152 are inserted into holes 134 of shaft 115. Bearing assemblies 161and 162 are pressed into holes 133 in ring 131.

Rod 113, with ball members 111 and 112 fixedly attached thereto, makesup cam 101. Rod 113 of cam 101 rotates in hole 114 of cam 102, whichincludes ball members 121 and 122 fixedly attached thereto. Shafts 115and 116 are rotatable with respect to ball members 111, 112, 121, and122.

Cams 101 and 102 cause shafts 115 and 116 to assume the same angle withrespect to the longitudinal axis of coupling yoke member 317.

How the ball cam centering mechanism works:

The kinematics of joints 100, 200, and 300 are identical to (or at leastvery similar to) that of a Double Cardan universal joint, a descriptionof which can be found in the Universal Joint and Drive Shaft DesignManual, AE-7, Published by the Society of Automotive Engineers, Inc.Like the Double Cardan joint, joints 100, 200, and 300 require the useof and internal support or centering device so that joints 100, 200, and300 are self-supporting and self-aligning. The use of internal supportis not necessary when end supports are supplied for the input/outputshafts (shafts 15, 16) such as in a marine stem-drive system. However,when only one end support is provided such as in automotive drivelines,axle driveshafts, and steering applications, the use internal support ora centering device is necessary.

The centering devices 10, 210, and 110 of joints 100, 200, and 300 areadvantageous over prior art centering mechanisms in the following ways:Centering devices of Double Cardan universal joints allow the joint tooperate a constant velocity at a maximum of two joint angles only.Because the ball and socket of the Double Cardan joint drifts out of thebisecting angle plane of the two joint halves and error or inequalitybetween the two joint halves is produced causing the joint to operate atnear but not true constant velocity. The effects of Double Cardancentering device location and function can be found on page 112 of SAE'sUniversal Joint And Drive Shaft Design Manual. The centering mechanismof joints 100, 200, and 300 allow the joint to operate at true constantvelocity at all joint angles from 0 to the joints maximum misalignmentcapability. True constant velocity operation is achieved as a result ofmaintaining the axis of both cams perpendicular to the bisecting angleplane of joints 100, 200, and 300 at all joint angles. When joint 100 isat a 0 degree angle the ball of cam 1 and the ball members of cam 2 areall in alignment. Movement of one of the shafts (15, 16) at an anglerelative to the longitudinal axis of the coupling yoke (117) istransmitted to the other shaft (16, 15) by the centering device (10) andthe centering device (10) causes the other shaft (16, 15) to likewisemove at the same angle relative to the longitudinal axis of the couplingyoke (117). This is accomplished by allowing cam 1 to rotate within cam2 resulting in the ball members on the end of cam 1 and cam 2 to beequally displaced.

The centering devices 10, 210, and 110 of joints 100, 200, and 300 areadvantageous over other centering mechanisms because they can providesupport at high joint angles with less lateral movement within thecoupling yoke (117, 217, 317). Reducing lateral movement of a centeringdevice allows designers to concentrate the mass of coupling yokes closerthe joints center of rotation thereby reducing the inertia excitation(vibration) caused by this components non-uniform motioncharacteristics. Limitations in high operating angle are produced as aresult of the large lateral displacement requirement of supportingmechanisms of Double Cardan joints resulting increased package size anddriveline disturbances.

As can be seen in the drawings, ball members 21, 22, 121, 122, 221, and222 each have spherical outer surfaces extending from a position atapproximately the 35th parallel in the southern hemisphere of the ballmember to approximately the 35th parallel in the northern hemisphere ofthe ball member. The amount of outer surface of the ball members 21, 22,121, 122, 221, and 222 is determined by the amount of shaft displacementdesired for the universal joint. Generally, the minimum amount of outersurface of ball members 21, 22, 121, 122, 221, and 222 is slightlylarger than the surface between the two latitudes corresponding to onehalf of the angular displacement of shafts 15, 16, 115, 116, and 215,216.

PARTS LIST

The following is a list of parts and materials suitable for use in thepresent invention:

1 cam (preferably made of ball members 11 and 12 fixedly attached to rod13) 2 cam (could be made of 52100 bearing steel having a hardness of 60HRC) 10 ball cam centering mechanism of the first embodiment of thepresent invention 11 first ball member of mechanism 10 (could be made of52100 bearing steel having a hardness of 60 HRC) 12 second ball memberof mechanism 10 (could be made of 52100 bearing steel having a hardnessof 60 HRC) 13 rod (could be made of 4140 alloy steel having a hardnessof 45 HRC) which is free to rotate within through bore 14 14 bore in cam2 15 shaft (4140 alloy steel) 16 shaft (4140 alloy steel) 17 dualpurpose rollers (could be made of 52100 bearing steel having a hardnessof 60 HRC) 18 bore in shaft 15 (could have a hardness, for example, of60 HRC to a depth of .040 inches) 19 cages supporting rollers 17 20seals sealing open end of bores 18 and 28 to ball portions 21 and 22 ofcam 2 to allow lubricating grease to fill bores 18 and 28 and to keepforeign objects out of bores 18 and 28 21 third ball member of mechanism10-first ball portion of cam 2 (could be made of 52100 bearing steelhaving a hardness of 60 HRC) 22 fourth ball member of mechanism10-second ball portion of cam 2 (could be made of 52100 bearing steelhaving a hardness of 60 HRC) 28 bore in shaft 16 (could have a hardness,for example, of 60 HRC to a depth of .040 inches) 31 ring 32 ring 41first pin projection of shaft 15 42 second pin projection of shaft 15 43first pin projection of shaft 16 44 second pin projection of shaft 16 51first pin member 52 second pin member 53 third pin member 54 fourth pinmember 61 first pin member bearing assembly 62 second pin member bearingassembly 63 third pin member bearing assembly 64 fourth pin memberbearing assembly 100 joint 101 cam (preferably made of ball members 111and 112 fixedly attached to rod 113) 102 cam (could be made of 52100bearing steel having a hardness of 60 HRC) 110 ball cam centeringmechanism of the second embodiment of the present invention 111 firstball member of mechanism 110 (could be made of 52100 bearing steelhaving a hardness of 60 HRC) 112 second ball member of mechanism 110(could be made of 52100 bearing steel having a hardness of 60 HRC) 113rod (could be made of 4140 alloy steel having a hardness of 45 HRC)which is free to rotate within through bore 114 114 bore in cam 102 115shaft (4140 alloy steel) 116 shaft (4140 alloy steel) 117 integralcoupling member and dual yokes (can be the same part as part 117 in U.S.Pat. No. 5,823,881, with similar or same pins interconnecting it to therings) 118 bore in shaft 115 (could have a hardness, for example, of 60HRC to a depth of .040 inches) 120 seals sealing open end of bores 118and 118 to ball portions 121 and 122 of cam 102 to allow lubricatinggrease to fill bores 118 and 128 and to keep foreign objects out ofbores 118 and 128 121 third ball member of mechanism 110-first ballportion of cam 102 (could be made of 52100 bearing steel having ahardness of 60 HRC) 122 fourth ball member of mechanism 110-second ballportion of cam 102 (could be made of 52100 bearing steel having ahardness of 60 HRC) 128 bore in shaft 116 (could have a hardness, forexample, of 60 HRC to a depth of .040 inches) 131 ring 132 ring 133holes of rings 131 and 132 134 holes in shaft 115 141 first pinprojection of shaft 115 142 second pin projection of shaft 115 143 firstpin projection of shaft 116 144 second pin projection of shaft 116 145holes of ring 131 and ring 132 149 holes in shaft 116 151 first pinmember of joint 100 152 second pin member of joint 100 153 third pinmember of joint 100 154 fourth pin member of joint 100 155 trunnion pin156 trunnion pin 161 first pin member bearing assembly of joint 300 162second pin member bearing assembly of joint 300 163 third pin memberbearing assembly of joint 300 164 fourth pin member bearing assembly ofjoint 300 165 bearing cup/bearing assembly of joint 300 166 cylindricalneedle rollers (could be made of 52100 bearing steel having a hardnessof 60 HRC) 167 cam ball race (made of, e.g., 8620 steel carberized to ahardness of 60 HRC or of 52100 bearing steel having a hardness of 60HRC) 168 three-piece friction ring 169 thrust bearing race 169 170 disksprings (such as National Disk Spring Part No. Am188207) 171 ballbearings 171 172 bearing cup/bearing assembly of joint 300 173 bearingcup/bearing assembly of joint 300 174 expansion pin (preferablyheadless) 175 bearing seal made of, e.g., rubber such as buna N 70Durometer hardness 176 expansion pin (preferably headless) 180 taperedopening of cam ball race 167 181 splines on rod 113 182 holes of rod 113191 splines on ball members 111 and 112 200 drive shaft constantvelocity joint 201 cam (could be made of 52100 bearing steel having ahardness of 60 HRC-preferably made of ball members 211 and 212 fixedlyattached to rod 213) 202 cam (could be made of 52100 bearing steelhaving a hardness of 60 HRC) 210 ball cam centering mechanism of thesecond embodiment of the present invention 211 first ball member ofmechanism 210 (could be made of 52100 bearing steel having a hardness of60 HRC) 212 second ball member of mechanism 210 (could be made of 52100bearing steel having a hardness of 60 HRC) 213 rod (could be made of4140 alloy steel having a hardness of 45 HRC) which is free to rotatewithin through bore 214 214 bore in cam 202 215 shaft (4140 alloy steel)216 shaft (4140 alloy steel) 217 integral coupling member and dual yokes218 bore in shaft 215 (could have a hardness, for example, of 60 HRC toa depth of .040 inches) 220 seals sealing open end of bores 218 and 228to ball portions 221 and 222 of cam 202 to allow lubricating grease tofill bores 218 and 228 and to keep foreign objects out of bores 218 and228 221 third ball member of mechanism 210-first ball portion of cam 202(could be made of 52100 bearing steel having a hardness of 60 HRC) 222fourth ball member of mechanism 210-second ball portion of cam 202(could be made of 52100 bearing steel having a hardness of 60 HRC) 223hole in ball member 221 228 bore in shaft 216 (could have a hardness,for example, of 60 HRC to a depth of .040 inches) 231 ring 232 ring 233holes of rings 231 and 232 234 holes in shaft 215 241 first pinprojection of shaft 215 242 second pin projection of shaft 215 243 firstpin projection of shaft 216 244 second pin projection of shaft 216 245holes of ring 231 and ring 232 246 holes of yoke 217 247 holes of yoke217 249 holes in shaft 216 251 first pin member of joint 200 252 secondpin member of joint 200 253 third pin member of joint 200 254 fourth pinmember of joint 200 255 trunnion pin 256 trunnion pin 257 pin 258 pin261 first pin member bearing assembly of joint 200 262 second pin memberbearing assembly of joint 200 263 third pin member bearing assembly ofjoint 200 264 fourth pin member bearing assembly of joint 200 265bearing cup/bearing assembly of joint 200 266 bearing cup/bearingassembly of joint 200 267 bearing cup/bearing assembly of joint 200 268bearing cup/bearing assembly of joint 200 274 expansion pin (made of,e.g., 8620 steel carberized to a hardness of 60 HRC or of 52100 bearingsteel having a hardness of 60 HRC) 275 spherical band (made of, e.g.,4340 steel) 276 expansion pin (made of, e.g., 8620 steel carberized to ahardness of 60 HRC or of 52100 bearing steel having a hardness of 60HRC) 277 ball race roller race (made of, e.g., 8620 steel carberized toa hardness of 60 HRC or of 52100 bearing steel having a hardness of 60HRC) 278 ball race roller race (made of, e.g., 8620 steel carberized toa hardness of 60 HRC or of 52100 bearing steel having a hardness of 60HRC) 279 ball race roller race (made of, e.g., 8620 steel carberized toa hardness of 60 HRC or of 52100 bearing steel having a hardness of 60HRC) 280 ball race roller race (made of, e.g., 8620 steel carberized toa hardness of 60 HRC or of 52100 bearing steel having a hardness of 60HRC) supporting rollers 282 281 splines on rod 213 282 cylindricalneedle rollers (could be made of 52100 bearing steel having a hardnessof 60 HRC) 283 outer bearing cup (made of, e.g., 8620 steel carberizedto a hardness of 60 HRC or of 52100 bearing steel having a hardness of60 HRC) 284 outer bearing cup (made of, e.g., 8620 steel carberized to ahardness of 60 HRC or of 52100 bearing steel having a hardness of 60HRC) 285 notch of bearing race 279 286 groove of bearing race 279 287spacer ring to add surface area to contact ball members 211 and 212 291splines on ball members 211 and 212 292 holes in rod 213 295 seals ofbearing cups 261, 262, 263, 264 296 roller bearings of bearing cups 261,262, 263, 264 300 universal joint 317 integral coupling member and dualyokes 346 holes of yoke 317

All measurements disclosed herein are at standard temperature andpressure, at sea level on Earth, unless indicated otherwise.

The foregoing embodiments are presented by way of example only; thescope of the present invention is to be limited only by the followingclaims.

What is claimed is:
 1. A universal joint comprising: (a) first andsecond shafts; (b) coupling means for transmitting torque from the firstshaft to the second shaft; (c) centering means interconnecting the firstshaft and the second shaft for causing the second shaft to move at thesame angle relative to the coupling means as does the first shaft, thecentering means comprising a first cam bearing longitudinally alignedwith a second cam bearing.
 2. The universal joint of claim 1, whereinthe first cam bearing is within the second cam bearing.
 3. The universaljoint of claim 1, wherein the first cam bearing is rotatable withrespect to the second cam bearing.
 4. The universal joint of claim 3,wherein the first cam bearing is within the second cam bearing.
 5. Auniversal joint comprising: (a) first and second shafts; (b) couplingmeans for transmitting torque from the first shaft to the second shaft;(c) centering means interconnecting the first shaft and the second shaftfor causing the second shaft to move at the same angle relative to thecoupling means as does the first shaft, the centering means comprising afirst cam bearing longitudinally aligned with a second cam bearing. 6.The universal joint of claim 5, wherein the first cam bearing is withinthe second cam bearing.
 7. The universal joint of claim 5, wherein thefirst cam bearing is rotatable with respect to the second cam bearing.8. The universal joint of claim 7, wherein the first cam bearing iswithin the second cam bearing.